A sharp increase in allergic disorders, such as bronchial asthma, allergic rhinitis, and atopic dermatitis, has been observed in the past decades, and current estimates suggest that at least about one fifth of the population is affected with some type of allergic disease. Since most of the current agents for treating allergies are symptomatic, and in view of the increase in the number of affected patients and the side effects that accompany long-term uses, more effective treatments have been desired (Non-Patent Document 1).
Lactobacilli produce favorable flavoring substances and have an ability to produce anti-bacterial substances such as lactic acid and bacteriocins. As such, they have been consumed through fermented milk and the like from ancient times in different parts of the world. Accordingly, they are known to be very safe microorganisms. Moreover, a recent double blind placebo test showed that administration of Lactobacillus rhamnosus GG (Lactobacillus rhamnosus ATCC 53103), which is a type of lactobacillus, suppressed the incidence of atopic diseases in high risk children by about 50% (Non-Patent Document 2). Thus, use of lactobacilli appears to be an easy and effective method for preventing and/or treating allergies without accompanying side effects.
To date, various agents for preventing and/or treating allergies using lactobacilli have been proposed. However, regarding Lactobacillus plantarum CCRC 12944 and Lactobacillus acidophilus CCRC 14079 described in Patent Document 1, although the ability of interferon γ-production from cultured cells was evaluated upon selection of the lactobacillus strains, the preventive and/or therapeutic effects for allergies when the lactobacilli are actually taken up by animals was not investigated. Moreover, although it is desirable due to safety issues to isolate microorganism-based probiotics from humans (Non-Patent Document 3), this factor was not considered in the context of selection of the lactobacillus strains in the case of the lactobacillus strains described in Patent Documents 2 and 3 (Lactococcus lactis subsp. lactis G50 and Lactobacillus paracasei KW 3110). Regarding the lactobacilli described in Patent Documents 2 and 4 (Lactococcus lactis subsp. lactis G50, Lactobacillus acidophilus CP 1613. Lactobacillus acidophilus L 92, and Lactobacillus fermentum CP 34), the researchers therein failed to consider bacterial resistance to a low pH environment in the stomach or to the bile acid in the intestinal tract, both of which are properties of probiotics, when selecting the lactobacillus strains (Patent Documents 2 and 4). In addition, the lactobacillus disclosed in Patent Document 3 (Lactobacillus paracasei KW 3110) was selected by using as an index the production of antigen-specific IgE antibodies in the systemic immunity induced upon intraperitoneal administration of antigens to mice (Patent Document 3). However, it is unlikely that therapeutic effects against food allergies are appropriately evaluated by using the antibody production in systemic immunity as an index. Food taken orally is absorbed by the intestinal tract, and at the same time, recognized by an immune system unique to the intestinal tract, one that is distinct from the systemic immune system, referred to as gut-associated lymphatic tissue (GALT), and that normally induces an oral immune tolerance. On the other hand, in some cases, it induces the production of IgE antibodies, thus leading to the development of food allergy. The mechanism by which food, which normally should induce immune tolerance, induces food allergy is not sufficiently elucidated to date; however, it is contemplated that at least both the intestinal and systemic immune systems are involved in the development of food allergies. Thus, it is unlikely that an evaluation of allergy-preventing effects using the systemic immune system reflects the therapeutic effects against food allergies.
Thus, given the current situation with the existing lactobacilli, there remains room for improvement when preparing agents for preventing and/or treating allergies of interest, or dietary compositions for preventing and/or treating allergies.    Patent Document 1: Japanese Patent Application Kokai Publication No. (JP-A) 2004-91491 (unexamined, published Japanese patent application).    Patent Document 2: JP-A 2004-18469.    Patent Document 3: Japanese Patent No. 3585487.    Patent Document 4: JP-A 2004-26729.    Non-Patent Document 1: Akahoshi M, Tamari M, Shirokawa T, “Recent Topics in Allergic Diseases”, Saishin Igaku, 58(2), pp. 7-14 (2003).    Non-Patent Document 2: Kalliomaki M, Salminen S, Arvilommi H, Kero P. Koskinen P. Isolauri E., “Probiotics in primary prevention of atopic disease: a randomised placebo-controlled trial”, Lancet, 357(9262), pp. 1076-1079 (2001).    Non-Patent Document 3: Naidu A S, Bidlack W R, Clemens R A, “Probiotic spectra of lactic acid bacteria (LAB)”, Critical Reviews in Food Science and Nutrition, 39(1), pp. 13-126 (1999).    Non-Patent Document 4: Ise W, “Progress in the studies of food allergy control; recognition of food allergen by the intestinal immune system”, Agriculture, Forestry and Fisheries Technical Research Journal, 24(5), pp. 9-14 (2001).